1. Field of the Invention
The present general inventive concept relates to an image printer, and more particularly, to an image printer in which a common filter is used to remove harmonic waves generated at a common operating frequency band of a fixing module to fix toner onto a print medium using high frequency power generated from a high frequency generator and a switch mode power supply module to supply operating power to the high frequency generator.
2. Description of the Related Art
FIG. 1 is a functional block diagram illustrating a conventional image printer in which a fixing module and a switch mode power supply module have separate filters for filtering harmonic waves of operating frequencies, respectively. Referring to FIG. 1, the conventional image printer includes a power source 110, a first filter 120, a second filter 130, a rectifier 140, a high frequency generator 150, a fixing part 160, a third filter 170, and a switch mode power supply (SMPS) part 180. The power source 110, the first filter 120, the second filter 130, the rectifier 140, the high frequency generator 150, and the fixing part 160 constitute the fixing module. The power source 110, the first filter 120, the third filter 170, and the switch mode power supply part 180 constitute the switch mode power supply module. The power source 110 supplies an AC current having a predetermined magnitude and frequency. The first filter 120 filters harmonic components generated during conversion of the AC current into a DC current. The AC current supplied from the power source 110 is converted into the DC current by the rectifier 140. The high frequency generator 150 is supplied with the DC current and generates a high frequency AC current. The generated high frequency AC current is supplied to the fixing part 160 having a heating part 165. The heating part 165 generates heat with resistance or inductance by using the high frequency AC current. A toner fixing part 168 fixes toner to a print medium by using the generated heat.
The switch mode power supply part 180 rectifies and converts the AC current supplied from the power source 110 into a DC current and generates a high frequency current necessary for the high frequency generator 150 of the fixing module from the converted DC current by using a high frequency generator (not shown).
Since the fixing module and the switch mode power supply module have different operating frequency bands, the fixing module and the switch mode power supply module have the second and third filters 130 and 170 for filtering the harmonic waves generated in the operating frequency bands thereof, respectively. However, when the temperature of the fixing part 160 is sensed and the frequency of the high frequency current supplied from the fixing part 160 is controlled according to the sensed temperature of the fixing part 160, the operating frequency of the high frequency current generated from the high frequency generator 150 varies in a predetermined frequency band. Accordingly, if the fixing module and the switch mode power supply modules operate at a common operating frequency band, it is possible to use one filter to filter harmonic waves of the common operating frequency band.